Winds at the time were blowing as hard as 65mph, according to the US National Weather Service.

Fourteen people survived, including seven who were injured when the boat went down, state police said. The four missing are presumed dead.

Duck boats, named for their ability to travel on land and in water, have been involved in other deadly incidents in the past. Five college students were killed in 2015 in Seattle when a duck boat collided with a bus, and 13 people died in 1999 when a boat sank near Hot Springs, Arkansas.

My deepest sympathies to the families and friends of those involved in the terrible boat accident which just took place in Missouri. Such a tragedy, such a great loss. May God be with you all!

Safety advocates have sought improvements and complained that too many agencies regulate the boats with varying safety requirements.

The boats were originally designed for the military, specifically to transport troops and supplies in the Second World War. They were later modified for use as sightseeing vehicles.

Passengers on a nearby boat described the chaos as the winds picked up and the water turned rough.

“Debris was flying everywhere,” Allison Lester said in an interview Friday with ABC’s Good Morning America.

Ms Lester’s boyfriend, Trent Behr, said they saw a woman in the water and helped to pull her into the boat. He said he was about to start CPR when emergency responders arrived and took over.

A spokeswoman for Cox Medical Centre in Branson said four adults and three children arrived at the hospital shortly after the accident. Two adults are in critical condition, and the others were treated for minor injuries.

Stone County Sheriff Doug Rader said an off-duty deputy working as security for the boat company helped rescue people after the boat turned over. Dive teams from several law enforcement agencies assisted in the effort.

Suzanne Smagala with Ripley Entertainment, which owns Ride the Ducks business in Branson, said the company was assisting authorities. She said this was the ride’s only accident in more than 40 years of operation.

In the hours after the accident, the lake was calm. But another round of thunderstorms passed within 10 miles of the area on Friday morning, and more storms were forecast for later in the day – some severe.

We are aware of a major incident that happened tonight on Table Rock Lake, and ask that you pray for those involved as well as law enforcement/first responders. Updates will come from Missouri Highway Patrol or the Stone County Sheriff’s Department.